Peplin Announces Positive Results of Phase IIa AK Trial

EMERYVILLE, California and BRISBANE, Australia 12
December 2007: Peplin, Inc. (ASX:PLI) today announced positive
preliminary results of PEP005-007, its Australian and New Zealand
based phase IIa actinic (solar) keratosis (AK) clinical trial. This
trial is the first in which PEP005 Topical for AK, Peplin’s
patient-applied topical gel, has been tested as a field-directed
investigational therapy on the face or face and scalp treatment
areas. AKs are common pre-cancerous skin lesions, caused by sun
exposure, a portion of which develop into skin cancer.

PEP005-007 is an open-label, multi-center clinical
trial designed to determine the optimal tolerated treatment regime
and evaluate the safety and efficacy of PEP005 Topical for AK when
applied to a 25 square centimeter area of skin on either the face
or the face and scalp for the treatment of AK.

The clinical trial evaluated formulation strengths
from 0.0025% to 0.025% (respectively, 1/10th of and equal to the
lowest formulation strength studied in PEP005-006, Peplin’s
clinical trial that evaluated the treatment of AK on non-facial
sites) at two and three consecutive day dosing regimes.

The trial established the maximum tolerated dose
(MTD) at 0.025% PEP005 Topical for AK applied daily for two
consecutive days as a field directed therapy to the face or face
and scalp sites.

The drug suggested a favorable safety profile and
for all doses studied at and below the MTD was well tolerated. Side
effects were consistent with Peplin’s earlier clinical trials
and comprised primarily transient local skin responses at the
treatment site. There were no drug related serious adverse events
reported.

In addition, a two or three day course of PEP005
Topical for AK demonstrated complete and partial clearance of AK
lesions in some patients tested at each formulation strength, with
the exception of the lowest formulation strength which demonstrated
partial clearance in some patients and no patients with complete
clearance.

Based upon an evaluation of the local toleration
profiles and complete and partial clearance rates demonstrated in
this clinical trial, Peplin believes it has identified a range of
doses, likely to be between 0.005% and 0.025% PEP005 Topical for AK
applied daily for two consecutive days, for further development in
treatment of AK on the face or face and scalp.

Finally, patient assessments in one of the
treatment groups (those patients who were scheduled to receive
three days of dosing) of convenience and ease of use, healing time,
cosmetic outcome, satisfaction compared to prior AK treatment and
overall patient satisfaction with PEP005 Topical for AK were, on
average, positive to very positive.

Peplin CEO Michael Aldridge said this trial delivered valuable
information about the activity of Peplin’s drug on AK sites
on the face and face and scalp.

“In particular we are pleased to have
identified a range of doses which when applied to the face and face
and scalp for two days are well tolerated and, which we believe may
have the potential to provide clinically relevant complete AK
clearance rates. We believe this information will be useful as we
prepare to meet FDA to discuss plans for our clinical program
through to NDA.”

Sydney dermatologist Dr Robert Rosen, who served as
the trial’s lead investigator said the study supported the
further development of the drug for treating AK on the face.

“AK is a skin condition associated with sun
exposure and sun damage. Accordingly, the face is an important
treatment site in the goal of reducing the potential for the
development of skin cancer. These results, in conjunction with
Peplin’s earlier clinical trial on non-facial sites, point to
a product which may, with further development, provide an
attractive, patient friendly and convenient treatment alternative
for treating AKs on both the body or face.”

Peplin intends to discuss the results of this trial
with the FDA, together with results of its previously completed
PEP005-006 non-facial AK clinical trial, pre-clinical,
manufacturing and other data. Peplin also intends to present plans
for a clinical program and other studies required to support a new
drug application (NDA) for PEP005 Topical for AK.

Peplin anticipates initiating the first clinical
study in this program in the first quarter of 2008.